**Comparative Evaluation of Different Techniques for Aflatoxin Detoxification in Poultry Feed and Its Effect on Broiler Performance**

T. Mahmood1, T.N. Pasha1 and F.M. Khattak2 *1Department of Food and Nutrition, University of Veterinary and Animal Sciences, Lahore, 2Avian Science Research Centre, SAC, Edinburgh, 1Pakistan 2UK* 

#### **1. Introduction**

Aatoxins (AF), the toxic secondary metabolites produced by *Aspergillus avus* and *Aspergillus parasiticus*, are a major concern in the poultry production. AF metabolites are stable and fairly resistant compounds to degradation (Dalvi, 1986; Park, 2002; Desphande, 2002; Lesson *et al.*, 1995; Feuell, 1996). These metabolites are usually produced during the growth of the *Aspergillus flavus*, *Aspergillus parasitcus* and *Aspergillus nominus* on certain foods and feedstuffs under favourable conditions of moisture, temperature and aeration (Goto *et al.*, 1997; Dutta and Das, 2001). Their toxicity depends on several factors including its concentration, the duration of exposure, the species, sex, age, and health status of animals (Jewers, 1990). Contamination of AF in feed causes aatoxicosis in poultry that is characterised by reduced feed intake, decreased weight gain, poor feed utilization (Tedesco *et al*., 2004; Bailey *et al*., 2006; Shi *et al.,* 2006, 2009), increased susceptibility to environmental and microbial stresses, and increased mortality (Leeson *et al.,* 1995). AF can also cause productive deterioration which is associated with changes in biochemical and hematological parameters (Denli *et al.,* 2004; Basmacioglu *et al.,* 2005; Bintvihok and Kositcharoenkul, 2006), liver and kidney abnormalities, and impaired immunity, which is able to enhance susceptibility to some environmental and infectious agents (Ibrahim *et al.,* 2000; Oguz *et al.,* 2003). AF has been reported to have effect on metabolism in poultry by decreasing the activities of several enzymes that are important in the digestion of starch, proteins, lipids and nucleic acids. Consequently, the activities of serum glutamate pyruvatate transaminase, serum gluatamate oxaloacetate tranferase and γ-glutamyl transferase are increased, primarily indicating hepatic damage (Devegowda and Murthy, 2005). AF is also known to interfere with metabolism of vitamin D, iron and copper and can cause leg weakness (Khajarern and Khajarern, 1999). Severe economic losses have been reported in the poultry industry due to aflatoxicosis (Kubena *et al.,* 1991, 1995). Ultimately, the transmission of AF and its metabolites from feed to animal edible tissues and products, such as liver and eggs, becomes a potential hazard for human health.

Comparative Evaluation of Different Techniques for Aflatoxin

Fish meal 3.00 Molasses 1.00

Calculated nutrient composition

**2.2 Experimental design** 

& DT by Sodium bentonite).

**2. Materials and methods** 

**2.1 Birds and diet** 

Detoxification in Poultry Feed and Its Effect on Broiler Performance 239

(Sodium bentonite or MycofixPlus), a study was conducted to compare different

Two hundred day-old commercial broiler chicks were randomly distributed to 5 dietary treatments with 4 replicates of 10 chicks each. During the first 21 days, all birds were fed on diet 1 which was the basal starter ration without any aflatoxin contamination (AF) and detoxifying treatment (DT). The ingredient composition of the basal diet is presented in Table 1. Experimental diets were prepared by replacing maize with contaminated maize having 70 ppb AF (Treatment 2) and were subjected to different DT (Treatment 3 to 5).

detoxification techniques and to further investigate its effect on broiler performance.

Ingredient Starter (%) Grower (%) Maize 50.70 60.00 Rice tips 10.00 10.00 Corn gluten meal 60 % 5.00 3.00 Soybean meal 10.00 6.00 Guar meal 5.00 5.00 Cotton seed meal 7.00 7.00 Rape seed meal 7.00 7.00

Di-calcium Phosphate 1.00 1.00 Lysine 0.30 0.35

M E (kcal/kg) 3000 3100 Crude protein 22.00 19.00 Crude fiber 4.53 4.48 Lysine 1.08 0.93 Methionine 0.49 0.45 Cystine 0.27 0.27 Met+Cys 0.88 0.80 Linoliec acid 1.21 1.36 Calcium 1.00 0.92 Phosphorous total 0.75 0.69 Phosphorus available 0.44 0.41

Table 1. Ingredient and nutrient composition of basal starter and grower diet of broilers.

day 7 and with oil based vaccine (intra muscular) at day 21 of the experiment.

On day 21, birds were fed on one of five experimental diets. Experimental diets were fed from day 21 to day 42 of the trial. Feed and water was available on *ad libitum* basis. All the birds were vaccinated against Newcastle Disease (N.D.), with Lasota strain eye droppings at

The experimental design consists of five dietary treatments; 1 (0 ppb AF & no DT); 2 (70 ppb AF & no DT); 3 (70 ppb AF & DT by Extrusion); 4 (70 ppb & DT by MycofixPlus); 5 (70 ppb

The occurrence of mycotoxin in nature is considered a global problem. However, in certain regions of the world, some of the mycotoxins are produced more commonly than others. Several *invitro* and *invivo* studies conducted in India, Pakistan, Egypt & South Africa suggested that AF are often present in substantial levels in mixed feed & ingredients (Devegowda and Murthy, 2005). Although, AF in feed and food is considered to be a major concern in warm and humid climatic regions of the world, however, caution must be exercised even in colder regions, when using feedstuffs imported from warm and humid countries.

With increasing knowledge and awareness of AF as a potent source of health hazards to both man and farm animals, producers, researchers and government organizations are making great effort to develop effective preventive management and decontamination technologies to minimise the toxic effects of AF content in foods and feedstuffs. In order to reduce the toxic and economic impact of mycotoxins, established regulations and legislative limits have been set for AF in poultry feed. Many countries follow a maximum permissible level of 20ppb for AF in poultry feed (CAST, 2003; FAO, 1995).

Appropriate pre and post-harvest contamination can be reduced by using appropriate agricultural practices. However, the contamination is often unavoidable and still remains a serious problem associated with many important agricultural commodities, which emphasizes the need for a suitable process to inactivate the toxin. Besides the preventive management, several approaches have been employed including physical (feed mill techniques, blending, extraction, irradiation, and heating), chemical (acids, bases, alkali treatments and oxidizing agents) biological treatments (certain species of fungi and bacteria) and solvent extraction to detoxify AF in contaminated feeds and feedstuffs (Coker *et al*., 1986; Piva *et al*., 1995; Parlat *et al.,* 1999). Since the beginning of 1990s, the adsorbent-based studies have also been reported to be effective in removing AF from contaminated feed and minimise the toxicity of AF in poultry (Ibrahim *et al.,* 2000). Among several adsorbents commercially available in the market, Zeolites (Miazzo *et al.,* 2000), bentonites (Rosa *et al.,* 2001, Pasha et al, 2007, 2008) and clinoptilolite (CLI), (Oguz and Kurtoglu, 2000; Oguz *et al.,* 2000 a, b), were preferred because of their high binding capacities for AF and their reducing effect on AF-absorption from the gastrointestinal tract.

All these methods cannot be used in practical feed manufacturing, because of the limitation of the nutrients decomposition, non availability of commercial methods and their residual effects. The increasing number of reports on detoxification of AF in poultry feed using different techniques has given rise to a demand for practical and economical detoxification procedures. Some of the physical treatments are reported to be relatively costly and may also remove or destroy essential nutrients in feed. Whereas, chemical methods are considered to be time consuming, expensive as they mostly require suitable reaction facilities, and are reported to have deteriorating residual effects on animal health (Coker, 1979; Coker *et al*., 1985). Certain legal implications are also associated with the use of different detoxifying methods. For example, European community (EC) is in favour of use of physical decontamination processes and sorting procedures. However, neither the use of chemical decontamination processes, nor the mixing of batches with the aim of decreasing the level of contamination below the maximum tolerable level is legal within the European Union (Avantaggiato *et al*, 2005). Although several mycotoxin detoxitoxifying or adsorbing techniques have been assessed independently however, limited information is available on the comparison of different techniques. To further understand the mechanisms of aflatoxin and detoxification of poultry feed by heat treatment (extrusion) and added adsorbents (Sodium bentonite or MycofixPlus), a study was conducted to compare different detoxification techniques and to further investigate its effect on broiler performance.
